When it comes to measuring weight, BMI is an acronym that everyone hates. Medical experts have long used the Body Mass Index as a rapid screening tool to quickly track certain patients into “code red” Management Plans – People whose weight is at risk for future health issues.
The problem is that BMI measures health risks by calculating height and weight. However, since muscle and bone weight is more than fat, measurements of BMI can overestimate the risks of people with muscular builds or larger frames. Conversely, BMI can underestimate health concerns in older people and those who have lost their muscles, according to the Harvard Chan School of Public Health in Boston.
Currently, the authors of the new study say that different approaches to weight measurement may be a more accurate way to predict future health problems. Bioelectrical impedance analysis, or BIA, uses undetectable currents, to measure not only the proportion of body fat, but also the lean muscle mass and water body weight.
This technology works in the following way: You are standing on the metal plate of the machine, holding your hands and thumbs in another metal attachment away from your body. Once it starts, the machine sends a weak current into the body. Body fat, muscles and bones all have different electrical conductivity, so the machine uses algorithms to determine lean muscle mass, body fat percentage and water weight.
“It turns out to be a stronger predictor of the risk of 15-year death in adults aged 20 to 49 than in BMI,” Arch Mainous III, the lead author of the study published Tuesday, was published in a family medicine journal.
Mainous, professor and vice-chairman of community health and family medicine research at the University of Florida School of Medicine, said that death from heart disease would result in people with high body fat measured by the BIA being 262% more likely to die than those with a healthy percentage of body fat.
“Now, using BMI did not flag any risk in this young population at all. This is not something we consider to be at high risk for heart disease,” said Dr. Frank Orlando, clinical associate professor at the University of Florida Health School.
“Think of the interventions you can do to stay healthy when you know this early. I think it’s a game changer to see how you should look at body composition,” Orlando said.
BMI is measured by dividing your weight by a square of height. (If you’re mathematically challenged like me, the National Institutes of Health has a free calculator.)
In the BMI world, weights between 18.5 and 24.9 are healthy weights, overweight between 25 and 29.9, 30 and 34.9 are obese, 35 and 39.9 are class 2 obese, and those above 40 are “severe” or class 3 obese. People are considered to be losing weight if their BMI is below 18.5.
Use BMI to measure health risk work at the population level. Countless studies have shown that greater BMI correlate with the development of all types of chronic diseases, including cancer, heart disease, type 2 diabetes, kidneys, and liver disease.
The location of BMI failures is at the patient level. Imagine a patient with “slender fat.” It is thin on the outside, but is troubled by fat masses wrapped around the main internal organs. Your BMI will be fine despite your health being at risk.
“These people are more likely to suffer from non-alcoholic fatty liver disease, have a higher chance of elevated glucose, increased blood pressure, and are generally more likely to cause inflammation,” said Mainous.
All of these health issues can be treated, stopped, and in some cases even reversed if caught early enough.
Doctors are aware of BMI issues, but many prefer it “because it is cheap and easy to practice,” said Mainous. “They want to use more direct measurements, such as Dexa scans, but they’re too expensive to be widely available, so everyone goes back to indirect measures of BMI.”
Dexa stands for dual energy x-ray absorption measurements and is the gold standard for body weight analysis. Patients usually travel to a hospital or specialty center for scans, as such machines can cost between $45,000 and $80,000. He said the cost of patients could easily range from $400 to $500 per scan.
“But we found that the newer version of bioelectrical impedance is very accurate and provides valid and reliable results,” Orlando said.
One note – at-home-based bioelectrical impedance products are not that accurate, says Andrew Freeman, director of cardiovascular prevention and wellness in Denver.
“They can be greatly influenced by how much fluid you have and how hydrated you are,” said Freeman, who was not involved in the new research. “For home measurements, only the ballpark is given. Clinic-based machines are more accurate.”
Is it time for a doctor to accept body fat measurements?
The new study analyzed data on 4,252 men and women who participated in the 1999-2004 federal survey called NHANES.
The technician measured each person’s body composition, including height, weight, and waist circumference. Additionally, all participants underwent clinic-based bioelectrical impedance analysis to measure body resistance to current.
The researchers then compared the data to the National Death Index until 2019 to see how many people died. After adjusting for age, race, and poverty status, this study found that BMI labeling someone as obese was not associated with a statistically significant risk of death from any cause when compared to a healthy BMI range.
However, people with high body fat measured in bioimpading analysis were 78% more likely to die for any reason, Mainous said. Measurements around my waist were also helpful, but not as accurate as my weight.
Adding that makes it more likely that you will die from the heart disease found in this study. It’s easy for doctors to use bioelectrical impedance analysis on patients, Orlando said.
“Let’s face it, the magnitude of the risk this research presents is enormous,” Freeman said. “It’s scary to think we might have used a BMI, an agent that may not have been that accurate over the years.”
The study shows how weighing can easily become a personalized drug, Freeman added.
“Imagine you came to your clinic,” he said. “They provided you with your body fat percentage and a personalized risk assessment. They spoke to you about exercise and other lifestyle changes and introduced you to a nutritionist.
“They gave you the opportunity to make these changes and helped with the medication if necessary. It would be amazing if the medical professionals could do this and save more lives.”
Inspired by the weekly roundups on living well, which have become simple. Sign up for CNN Life but a better newsletter for information and tools designed to improve your happiness.
